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以MnPO4.H2O、FePO4.2H2O为锰源和铁源,碳酸锂为锂源,葡萄糖为还原剂和碳源,采用高温碳热还原法,一步制备了改性的锂离子电池正极材料LiMn0.45Fe0.55 PO4/C,并讨论了合成温度对材料的影响。采用X射线衍射、扫描电子显微镜和充放电测试等手段,对最终产物的物相、形貌和电化学性能进行了表征。结果表明:在500～600℃可以制备LiMn0.45Fe0.55PO4/C固溶体材料。室温条件下充放电测试表明:600℃制备的LiMn0.45Fe0.55PO4/C具有最好的电化学性能,以15、75 mA/g和150 mA/g进行充放电,首次放电比容量分别为146.6、133.5 mA h/g和124.1 mA h/g,50次循环后容量保持率分别为97.5%、95.8%和97.6%;以300 mA/g的电流密度放电,首次放电比容量达到94.4 mA h/g。材料在55℃时电化学性能明显优于25℃的结果。
Abstract：LiMn0.45Fe0.55 PO4/C,as a cathode material of lithium ion batteries,was prepared with MnPO4·H2O,FePO4·2H2O and Li2CO3 as precursors and glucose as both reducing agent and carbon source by one-step carbothermal reduction.The effect of synthe-sis temperature on the performances of LiMn0.45Fe0.55PO4/C composites was investigated.The morphology and microstructure of the products were characterized by X-ray diffraction and scanning electron microscopy.The results show that LiMn0.45Fe0.55PO4/C solid solution can be prepared from 500 to 600 ℃.As an electrode material for rechargeable lithium ion batteries,the solid solution pre-pared at 600 ℃ exhibited a superior electrochemical performance.The initial discharge capacity of the sample reached 146.6,133.5,124.1 and 94.4 mA?h/g at the current density of 15,75,150 mA/g and 300 mA/g,respectively.In addition,this sample showed a good cycle performance.After 50 cycles it retained 97.5%,95.8% and 97.6% of the initial discharge capacity at 15,75 mA/g and 150 mA/g,respectively.It was indicated that the electrochemical performance of the sample at 55 ℃ was better than that at 25 ℃.
[1]PADHI A K,NAUJUNDASWAMY K S,GOODENOUGH J B.Phos-pho olivines as positive-electrode materials for rechargeable lithiumbatteries[J].J Electrochem Soc,1997,114(4):1188-1194.
[2]NISHI Y S.Lithium ion secondary batteries:past10years and thefuture[J].J Power Sources,2001,100(1/2):101-106.
[3]KIM D K,MURALIDHARAN P,LEE H W.Spinel LiMn2O4nanorodsas lithium ion battery cathodes[J].Nano Lett,2008,8(11):3948-3952.
[4]LEE J W,PARK M S,ANASS B.Electrochemical lithiation and de-lithiation of LiMnPO4:Effect of cation substitution[J].ElectrochimActa,2010,55:4162-4169.
[5]YAO J,BEWLAY S,WANG G X.Characterisation of olivine typeLiMnxFe1-xPO4 cathode materials[J].J Alloys Compd,2006,425:362-366.
[6]MOLENDA J,OJCZYK W,MARZEC J.Electrical conductivity andreaction with lithium of LiMnyFe1 yPO4 olivine-type cathode materials[J].J Power Sources,2007,174:689-694.
[7]蒋永,赵兵,万小娟,等.气相沉积碳包覆磷酸铁锂的制备及性能[J].硅酸盐学报,2008,36(9):1295-1299.JIANG Yong,ZHAO Bing,WAN Xiaojuan,et al.J Chin Ceram Soc,2008,36(9):1295-1299.
[8]刘素琴,张建峰,黄可龙,等.锰酸锂/碳纳米管复合电极的电化学特性[J].硅酸盐学报,2008,36(9):1319-1324.LIU Suqin,ZHANG Jianfeng,HUANG Kelong,et al.J Chin CeramSoc,2008,36(9):1319-1324.
[9]BOONCHOM B,YOUNGME S,MAENSIRI S,et al.Nanocrystal-line serrabrancaite(MnPO4.H2O)prepared by a simple precipitationroute at low temperature[J].J Alloys Compd,2008,454:78-82.
[10]WAGEMAKER M,BRIAN L E,HECHT D L,et al.Proof of superva-lent doping in olivine LiFePO4[J].Chem Mater,2008,20:6313-6315.
[11]CHUNG S Y,BLOKING J T,CHIANG Y M.Electronically conductivephospho-olivines as lithium storage electrodes[J].Nat Mater,2002,22(09):123-128.
[12]PROSINI P P,LISI M,ZANE D,et al.Determination of the chemicaldiffusion coefficient of lithium in LiFePO4[J].Solid State Ionics,2002,148:45-51.
[13]YAMADA A,LIU K Y.Reaction mechanism of the olivine typeLix(Mn0.6Fe0.4)PO4(0≤x≤1)[J].J Electrochem Soc,2001,148(7):A747-A754.
[14]BAEK Dong-Ho,KIM Jae-Kwang,Shin Yong-Jo,et al.Effect of firingtemperature on the electrochemical performance of LiMn0.4Fe0.6PO4/Cmaterials prepared by mechanical activation[J].J Power Sources,2009,189(1):59-65.
[15]ZHANG S S,ALLEN J L,XU K,et al.Optimization of reactioncondition for solid-state synthesis of LiFePO4-C composite cathodes[J].J Power Sources,2005,147:234-240.
基本信息:
DOI：10.14062/j.issn.0454-5648.2011.10.008
中图分类号:TM912
引用信息:
[1]杨则恒,赵刚,张卫新.锰掺杂磷酸铁锂/碳正极材料的制备及电化学性能[J].硅酸盐学报,2011,39(10):1608-1612.DOI:10.14062/j.issn.0454-5648.2011.10.008.
基金信息:
国家自然科学基金(20871038,20976033);; 安徽省教育厅资助项目(TD200702);; 国家大学生创新基金(101035925)资助
2011-09-27
2011-09-27
2011-09-27